This invention relates to cytocentrifuges, that is to say, centrifuge machines for the centrifugation of small samples of, e.g., body fluids such as cerebrospinal fluid, for separating and depositing cells and other solids suspended in the fluid in a manner permitting examination thereof by microscopy. Such cytocentrifuges are routinely used in hospital and other laboratories in diagnostic and investigative procedures and need therefore to be capable of being quickly set up to effect centrifugation of a first set of samples and of being quickly and easily reloaded for the centrifugation of second and subsequent sets of samples. Moreover as many of the materials that have to be subjected to centrifugation by such a machine may be toxic or release toxic or noxious matter during centrifugation, the construction of the machine must lend itself to loading and unloading of samples in a suitable containment zone such as a fume cupboard, and also allow of easy cleansing and sterilization of those components liable to come into contact with samples or other released matter.
Cytocentrifuges currently in use provide a sample chamber of generally tubular form that during the centrifugation operation is aligned with a radius to the vertical axis of rotation and has its outer end closed by a microscope slide or the like providing a surface for receiving deposited cells and other solids, the junction between the chamber and this receiving surface being sealed by an annulus of absorbent material such as filter card that both prevents leakage of the liquid component of the sample and absorbs this liquid so as to leave the cells and other deposited solids as a dry layer on the receiving surface at the conclusion of the centrifugation operation.
Various arrangements are in use or have been proposed for effecting the required conjunction of the sample chamber, receiving surface and filter/seal but typically these involve an assembly operation to be carried out upon or in conjunction with the rotating carrier of the centrifuge and that typically carries a number of symmetrically disposed sample chambers with associated receiving surfaces and filter/seals. These arrangements are generally tedious and inconvenient to manipulate, especially when the material being centrifuged, and any centrifuge components coming into contact therewith, must all be handled under conditions of containment to prevent escape of toxic or noxious matter.
One object of the present invention is therefore to provide a cytocentrifuge that avoids these disadvantages of the prior art constructions and that lends itself to rapid loading, unloading and reloading with samples, especially under conditions of containment, to allow of a high rate of utilization of the machine.
A further object of the invention, achieved in preferred embodiments, is to provide a cytocentrifuge capable of meeting the anticipated requirement for such machines to provide sealed containment of the carrier and sample chambers during operation and permitting loading and unloading to be accomplished in a containment zone, preferably without the need for the machine itself to be located in such a zone.